The Visual Memory Unit (VMU), referred to as the Visual Memory(ビジュアルメモリ) or VM (and VMS) in Japan is the de facto "memory card" for the Sega Dreamcast. While its most basic function is as a removable storage device, the VMU can also serve as an auxiliary display during normal gameplay and, through the use of additional software, it can act as a console independent of the Dreamcast.

Contents

Hardware

The introduction of the VMU was considered quite radical in 1998, for as well as being a means of storing Dreamcast data, it acts as its own independent handheld "console", capitalising on a craze started by Bandai with its Tamagotchi device in late 1996. When plugged into a Dreamcast controller it can act as an extra screen (an idea that Nintendo would adopt with its Nintendo GameCube and Game Boy Advance connectors, and eventually its Wii U console), but if removed it becomes a system with its own D-Pad, , and SLEEP buttons.

In order to function on its own, a VMU requires two CR2032 batteries, which can lead to problems. It does not require batteries in order to function within a Dreamcast controller (when the controller is connected and the system is powered on), but if the VMU lacks power it will make a high pitched warning screech during the console's bootup to alert the user.

Two VMUs can be connected together (another idea copied from Bandai, this time in its 1997 Digital Monster range, opening up new possibilities such as transferring data or playing two-player games.

Like the controllers and console, there are many different flavours of VMU in terms of colours. The colours vary depending on the market - in Japan there were many novelty VMUs, often inspired by games. In North America, translucent coloured VMUs were released, while in Europe very few coloured VMUs were sold.

The VMU technically debuted four months before the Dreamcast console, with the release of the Atsumete Godzilla: Kaijuu Dai Shuugou VMU in July 1998. As well as being a self-contained game in itself, it can be treated as a Dreamcast memory card.

Criticism

While the VMU is considered an integral part of the Dreamcast console, the built-in screen and its arguably superfluous features led to a high price point when compared to memory cards of the PlayStation and Nintendo 64. Furthermore, initial shipments of Dreamcast consoles did not come with VMUs, and as the Dreamcast has no built-in memory (unlike the Sega Saturn), an extra purchase was required to save games.

Sega also did not offer an official non-screened memory card until December 2000, when the Dreamcast 4x Memory Card was released in Japan. The "4x" in this instance symbolises the 512kB of data available to users - standard VMUs only have 128kB, of which the widely publicised "VMU games" would usually take up most of it. In a practical sense, this meant anyone wanting to play, for example, Chao Adventure, a free VMU download in Dreamcast launch title Sonic Adventure would be better off reserving a VMU specifically for this purpose - the few remaining memory blocks after the download would not serve particularly useful for many games.

VMUs pre-date a period in video games where built-in lithium-ion rechargable batteries (seen in the Game Boy Advance SP and newer) were not the norm. This means batteries need to be replaced manually on a fairly regular basis. When a Dreamcast system is turned off, no signal is sent to the VMUs to shut down, and so operate on their own power source for a short period of time before automatically switching themselves off. If left unchecked, this can cause VMUs to drain power just by being plugged into a Dreamcast console.

Reading Save Data

When reading save data from the memory manager on the Sega Dreamcast BIOS, it will appear in this format.

Save Data

Name

File Name

Comment

File Size

Name of the file.

Name of the file as it appears within the system.

Additional Information of File.

Number of Blocks Used.

How each file is named and what the comments field represents depends on how the developer has written each descriptor. When reading other articles on Sonic Retro and Sega Retro, keep in mind these common symbols represented in the wiki to determine the text as these variables are likely to differ when viewing on the Memory Manager.

US

The U.S. standard VM is undistinguisable from the Japanese counterpart. However, the colour series has slightly darker casing and has grey (instead of white) buttons (notice the starking difference between the Dreamcast inscription and the button colours). The US red and US blue Japanese VMs described above are a domestic release of their overseas versions, sporting the U.S. grey buttons and are only distinct by their different packaging.

Model No

Reference

Product

Box

Notes

MK-50120

Visual Memory Unit (standard)

MK-50121

Visual Memory Unit (clear blue)

MK-50122

Visual Memory Unit (clear green)

a similar (or same) is included with the Holiday Gift Pack.

MK-50123

Visual Memory Unit (clear red)

a similar (or same) is included with the Holiday Gift Pack

MK-50124

Visual Memory Unit (clear yellow)

MK-50125

Visual Memory Unit (clear black)

Data in italics might not be accurate.

Europe

The standard PAL VM is different from the Japanese and U.S. devices as it does not have a spiral next to the Dreamcast inscription, and the inscription itself is made in a larger font.